From 36bade7efbc9a53237cf8a9af61754dbea85e007 Mon Sep 17 00:00:00 2001
From: glepnir <glephunter@gmail.com>
Date: Sat, 11 Apr 2026 22:14:27 +0800
Subject: [PATCH] fix(highlight): preserve inherited colors when update=true
 breaks links #38750

Problem: Breaking a link with update=true loses colors inherited from
the linked group.

Solution: Copy color indices from the linked group so inherited colors
remain visible in :hi output.

(cherry picked from commit 01567ad4f6582579f1ac3d232cd6d8071f58ef17)
---
 src/nvim/highlight_group.c             |  8 ++++++++
 test/functional/api/highlight_spec.lua | 14 ++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/nvim/highlight_group.c b/src/nvim/highlight_group.c
index 99d505285e..4eb9f08c4c 100644
--- a/src/nvim/highlight_group.c
+++ b/src/nvim/highlight_group.c
@@ -919,6 +919,7 @@ void set_hl_group(int id, HlAttrs attrs, Dict(highlight) *dict, int link_id)
 
   HlGroup *g = &hl_table[idx];
   g->sg_cleared = false;
+  int old_link = g->sg_link;
 
   if (link_id > 0) {
     g->sg_link = link_id;
@@ -965,6 +966,13 @@ void set_hl_group(int id, HlAttrs attrs, Dict(highlight) *dict, int link_id)
       }
     } else if (!update) {
       *cattrs[j].dest = kColorIdxNone;
+    } else if (old_link > 0 && cattrs[j].val >= 0) {
+      // Copy color indices from the linked group so inherited colors remain visible in :hi output.
+      HlGroup *linked = &hl_table[old_link - 1];
+      int linked_idx = (j == 0) ? linked->sg_rgb_fg_idx
+                                : (j == 1) ? linked->sg_rgb_bg_idx
+                                           : linked->sg_rgb_sp_idx;
+      *cattrs[j].dest = (linked_idx != kColorIdxNone) ? linked_idx : kColorIdxHex;
     }
   }
 
diff --git a/test/functional/api/highlight_spec.lua b/test/functional/api/highlight_spec.lua
index 840fd54423..5da20bf74f 100644
--- a/test/functional/api/highlight_spec.lua
+++ b/test/functional/api/highlight_spec.lua
@@ -285,11 +285,21 @@ describe('API: set highlight', function()
     eq(tonumber('0x00ff00'), hl.fg)
     eq(true, hl.italic)
 
-    api.nvim_set_hl(0, 'LinkedGroup', { link = 'Normal' })
-    api.nvim_set_hl(0, 'LinkedGroup', { bold = true, update = true })
+    api.nvim_set_hl(0, 'NamedColor', { fg = 'red', bg = 'blue' })
+    api.nvim_set_hl(0, 'LinkedGroup', { link = 'NamedColor' })
+    api.nvim_set_hl(0, 'LinkedGroup', { bold = true, fg = 'green', update = true })
     hl = api.nvim_get_hl(0, { name = 'LinkedGroup' })
     eq(nil, hl.link)
     eq(true, hl.bold)
+    eq(
+      'LinkedGroup    xxx cterm=bold gui=bold guifg=Green guibg=Blue',
+      n.exec_capture('hi LinkedGroup')
+    )
+    api.nvim_set_hl(0, 'LinkedGroup', { bg = '#121314', update = true })
+    eq(
+      'LinkedGroup    xxx cterm=bold gui=bold guifg=Green guibg=#121314',
+      n.exec_capture('hi LinkedGroup')
+    )
 
     -- underline style flags: false must not corrupt other styles
     local unders = { 'underline', 'undercurl', 'underdouble', 'underdotted', 'underdashed' }